Cans and method of canning



April 21, 1 L. FRIED ETAL CANS AND METHOD OF CANNING Filed Sept. 2, 1960 FIG.|

INVENTORJ Louis Fri ed D Andrea BYA. RGlph M 1 771m United States Patent 3,130,059 CANS AND lflTHOD 9F CANNENG Louis Fried, East Orange, N.J., and A. Ralph DAndrea, Philadelphia, Pa.; said DAndrea assignor of 17.557 to Herbert M. Beitel, Chicago, Ill.

Filed Sept. 2, 1960, Ser. No. 54,543 4 Claims. (Cl. 991S1) This invention relates generally to canning and more particularly to a canning method or process and a can utilizable in connection therewith.

This application is a continuation-in-part of application Serial No. 655,297, filed April 26, 1957, now abandoned.

The primary object of this invention is to provide a can and method of canning whereby in following the method and the utilization of the particular can, the can itself is such that it is more stable and less apt to fracture or rupture or deteriorate in any other way either interiorly or exteriorly thereby lasting longer than any known can, and the contents of the can itself preserved better and longer than the contents in cans now presently used.

It is a known fact in the canning industry that, up to the present time, there are certain established and approved standmds, and such standards are usually met in the canning industry but have remained substantially the same for a long period of time and have not been materially improved. Stating the present invention another way, it is to be said that herein there is disclosed ways and means whereby the entire standard of canning is indeed improved and to a great extent as will be seen hereinafter.

In speaking about standards of canning, it is a well known fact that certain commodities, such as beer and ale for instance, and other such commodities that are or may be carbonated or may evolve gases either acid or alkaline, when placed in present-day cans and canned under present standards, have a relatively short shelf life for a certain period of time wherein it would be safe to utilize the contents for human or other consumption and the cans have a relatively low resistance to fracture. By the utilization of applications ways and means, the shelf life or length of time that such commodities, as beer, carbonated beverages or other commodities that may evolve gases of the nature stated and create pressures within the can, may be kept for human consumption is relatively long and is increased many, many times, and cans of the present invention having a relatively high resistance to fracture, for instance such cans containing beer, not under refrigeration, have been kept in a state for human consumption as long as about two years and under varying conditions such as very cold and very hot and intermediate temperatures and under modes of shipment, such as air and surface transportation.

These said cans of the present invention, under the aforesaid conditions and the length of keeping time of the contents thereof, did not buckle or fiacture or leak in any way and the closing of the cans resulted in a very effective hermetic seal and, incidentally, these cans were not made of a heavier gauge metal, both as regards the body or the closure for the body, than presently known cans for beer.

In referring to presently known cans, reference is had to presently known cans such as those cans containing beer, and the can body is usually of metal as are the end closures thereof and there is a longitudinally extending side seam and the can ends are seamed to the respective ends of the can body.

With regard to the present invention, the phenomena of the long shelf life or keeping qualities of the can contents and the high resistance of the can to fracture is indeed a very recent discovery and actually resulted from 3,130,059 Patented Apr. 21, 1964 some physical and structural characteristics of the can structure hereinafter referred to and the same were determined as the result of continuous and extended tests and research especially with regard to the present invention and the canning industry as it exists at the present time.

Present day cans, regardless of whether they contain beer or some other commodity, must of course be opened in order to dispense the contents thereof and this means that they are opened either by a puncturing type of cutter, or a rotary type cutter or the other type cutter where the end of a blade is punched into the can and the same worked around the edge near the seam.

In opening cans, as fioresaid, and opening by any other manner, if there is any, naturally metal is going to be separated when cut and slivers or flecks of the metal being cut are deposited within the container and imbibed by the consumer.

In the present invention, the can, either in its top Cl0 sure, wall portion or some other suitable place, has a precut opening therein and this opening is actually preferably made in at least one end closure of the can and this opening is made prior to the application of the end closure to the can so that there is no possibility of any flecks or slivers of metal being deposited in the can at any time. Then, too, this opening in the can top, contrary to what may be thought to result, namely a weakening thereof, has actually in combination with a backing up means for the opening, resulted in a strengthening of the can and, moreover, and in addition thereto, this opening results in a dissipation of the stresses that result from the pressures within the can when such commodities as beer, carbonated beverages or the like are packaged therein.

In a more specific sense, applicant provides the precut opening in at least one, or if desired both, can end clo sures, and a simple means of backing up that opening from the inner side of the can end closure. With the opening and backing up means, is used, for example, a piece of frangible metal foil, preferably aluminum, which is at least of slightly greater dimensions than the backing up means and extends thereover. This frangible metal foil preferably is of substantially the same size and dimensions as the can end closure itself and has its marginal edge portions formed with the can closure into a seam to permanently afiix the closure to the can wall. In some instances, it would be desirable that the back-up means be an opening device for use in rupturing and cutting the frangible metal foil about the said opening and this opening device may be of the form shown in a copending application mentioned hereinafter. Obviously when it is not desired to utilize an opening device such as in the copending application, then all that is required is, as aforesaid, some means for backing up the opening so that if the contents of the can is under pressure or pressurized in any respect, the metal foil will not be ruptured or punctured accidentally through the opening in the end closure of the can.

The physical characteristics of the can and the opening in the end closure thereof, and the opening device if used, are substantially as disclosed in the copending applications, but the important features of this invention are the discovery of the keeping qualities for the contents of the can as well as the life of the can itself and particularly when the can is utilized for packaging beer, soft drinks, carbonated, or other beverages which may be of a character to react with metal of the can, or be pressurized.

The preformed opening in the end closure or other part of the can, if it be desirable, not only may be utilized for the purpose of preventing rupture by relieving the stresses in the can but for receiving the contents of the can or dispensing the contents thereof.

One aspect of the invention relates to the art of packaging commodities and more particularly to the art of canning liquids either alcoholic or non-alcoholic, such as beer and carbonated beverages of the soft drink variety.

Sanitary cans or containers as presently made and used to can beer are and have been so constructed as to hold the high pressure generated in the filled can or container during pasteurization. A pressure about 90 pounds per square inch is usually reached during this pasteurization process. If, for any reason, the pressure is unduly increased, the can or container will rupture or buckle and usually buckles at the side seam cross-over at either end. Thus, the can or container will be rendered defective as well as the contents thereof.

With the development of the canning of carbonated beverages of the non-alcoholicor soft drink variety, much higher pressures are reached than those generated by beer under the conditions above set forth and the problem which this has raised has caused manufacturers to attempt to reach a solution by making stronger side seams and making the ends of the can or container of thicker tin plate than that heretofore used and of course increasing costs. This has been done with the hope of increasing the strength of the can or container in order to hold the greater pressure generated by the carbonated beverage.

Another object is to solve the problems referred to and thereby make possible the canning of carbonated beverages containing a larger amount of CO than the carbonated beverages presently canned such as white soda and the like without having to resort to using cans having a stronger side seam or end closures of increased thickness by the provision of a method and means of increasing the stability of the can or container so that it will withstand pressures far in excess of the presently known and used can or container constructions.

' Another problem encountered in the canning of beer or carbonated beverages according to present practice, is metal exposure, which problem is created as a result of the manufacturing of cans at a high rate of speed.

It often happens that when the body of the can is being seamed some metal exposure takes place by the abrasion or rupturing of the lacquer on the tin plate in the seaming operation and as a result metal is exposed.

Also it occurs many times that after the can is filled and the closing operation is taking place in the closing machine, metal exposure occurs or is brought about along the inner edge of the line of contact between the lid of the can and the body of the can. This is a result of many factors which cannot always be controlled, namely by slipping or sliding of the metal end when it is dropped on the filled can and is ready for the closing operation. A torque effect is often produced when the chucks of the closing machine bear down on the lid causing a slight twist to take place in connection with the closing operation.

When the foregoing condition arises and the protective coating of the lacquer or vinyl material overlying the tin plate coating is ruptured or abraded, and the tin plate coating over the steel base is also sometimes ruptured or abraded, there results a shortened shelf life of the canned product, be it beer or carbonated beverage, or be it acid or alkaline. In fact, in the case of carbonated beverages, the product deteriorates much faster due to the high acid content of the product. Deterioration is due to the fact that the steel exposed to contact with the beer or carbonated beverage produces iron salts which impart an objectionable taste to the canned product. In view of the foregoing, a further object of the invention is to provide a novel means or method of preventing deterioration of canned beer and carbonated beverages when abrasions or ruptures are caused in the lacquer or vinyl coating or the tin plate by effecting deposition of a protective metal over or in the abraded part to thereby prevent reaction between the acid of the receptacle contents and the metal.

The method and means whereby the foregoing and possibly other objects may be obtained will be described in connection with the accompanying drawing wherein:

FIG. 1 is a view partly in longitudinal section and partly in elevation of a metal can or container such as is customarily employed for merchandising beer and carbonated beverages and showing a preferred means for carrying out the invention;

FIG. 2 is an enlarged detail of the seam between an end wall and the side wall of the can or container;

FIG. 3 is an enlarged detail in section of a portion of the can side wall showing the difierent coatings making up the wall structure.

As hereinbefore stated, cans or containers as presently made, when subjected to excessive internal pressure for any reason, buckle at the side seam cross-over which is at the points designated 10' in FIG. l.

in carrying out the present invention whereby rupture or failure of the can structure at these points and at other points is avoided, the can, which is here generally designated C, has either of its end walls 12 and/or 14 provided with an opening of proper size and any suitable shape. In the illustration, the wall 14 only is shown with an opening which is designated 16.

The can structure here illustrated is of approximately the same design shown in our copending application, now Patent No. 2,821,326, wherein the opening 16 is described as a pour opening through which the contents of the can or container may be discharged when the container is opened in the manner intended by the employment of the illustrated opener structure but the opening formed for the purpose of accomplishing the desired re sults according to the present invention does not need to be of any specified form or made for use as a pour opening.

The numeral 18 designates a metal plate or body which is disposed against the inner side of the wall 14 in covering relation with the opening '16. In the illustration here given, this plate 1-8 forms a part of an opener device which is generally designated- 20 and which is illustrated in detail in the patent above identified. However, it is to be understood that while there is here shown an opener of the character referred to in connection with the present invention, the carrying out of the present invention does not require the use or presence of an opener device but that the employment of any suitable metal sheet or plate such as is here shown and designated 18 may be made use of.

Under the opening 16 formed in the can or container end wall, there is placed or inserted a frangible liner 21 of metal having the inner surface covered by a suitable lacquer or synthetic resin such as a vinyl resin as indicated at 21b and this liner with the lacquer or resin is seamed into the end seam of the can, which end seam is here designated 210 so that there will be produced a hermetic seal or, in other words, so that the can is rendered hermetically sealed.

The frangible liner, when of metal, preferably is formed of sheet aluminum of suitable weight.

By the procedure of forming an opening of any suitable size or shape in either end wall, or both end walls, there is accomplished a condition whereby the stresses created by. the pressure within the can are broken and relieved when the stresses reach the opening or cut-out in one of the can ends.

This breaking of the continuity of the stresses on the metal of the can or container caused by the pressure in the can or container allows the can or container to achieve a greater resistance to the pressures within the same. The result thus attained is that the can or container will not buckle at the end where the opening or out-out has been made and if and when buckling does take place at any seam (except as noted) the buckling happens only when the pressure in the can or container of this invention has reached a pressure far in excessof the pressure that the containers or cans now on the market can withstand.

Pressures deliberately built up for test purposes in cans of the present invention to determine the resistance qualities of the same, were developed to a terrifically high degree before rupture of the can resulted, and which said high degrees of pressure were greatly in excess of any pressures which could be expected to be built up in the cans under normal conditions of use.

The structure illustrated is shown as containing or being substantially filled with liquid L which may be beer, ale, or other alcoholic beverages or carbonated non-alcoholic beverages.

Cans or containers employed for containing such liquids have, conventionally, a base metal 22 of steel which is covered or coated on both surfaces with tin plate 23 and the inner surface of the wall has applied thereover a lacquer or vinyl coating designated 24.

Briefly, one method of forming and filling the cans of the present invention consists of applying a can top with a preformed opening, to one end of the can body and seaming it thereto and inverting such can and filling the can with beer or other flowable material and then placing on the other end a top or end similar to that one already thereon, or a conventional can end, and complet ing by the sealing of the can end, thus obtaining a can of superior qualities, including the can per se as well as the shelf life thereof and, of course, the contents.

The carrying out of the present invention for the purpose of preserving the contents of the can or container against deterioration resulting from abrasion of the lacquer or vinyl coating 24 and exposure of the tin coating, or the abrasion of the tin coating, and lacquer and exposure of the steel base metal, is as follows.

It is known that in the simplest galvanic cell, the electric flow through metallic contact is from plus to minus. However, the ionic flow (flow of ions which carry an electric charge) within the solution is from minus to plus. Therefore, in any solution, the ionic flow is from a metal with a higher negative rating to one with a lower negative rating.

In View of the foregoing, therefore, by attaching or inserting a frangible metal liner, such as that here shown and designated 21, having a higher negative rating than the tin plate or steel base thereunder, to the can end and then seaming the said frangible metal liner to the seam of the can end, and the can body as indicated at 21a, there is created a situation whereby the metals of different negative rating are closely bound together. Bearing in mind that the contents of the can or container is acid in chemical composition, the metallic frangible liner having a higher negative rating than the tin plate or steel base metal with which it will have contact, will result in the flow of ions from the frangible metal liner to the tin plate or steel base. This results in a lessening or complete elimination of any undesirable contamination of the contents of the can from exposure of the contents to the bare or uncoated tin plate or steel base.

Any suitable metal, having a higher negative rating than steel base, can be used for the frangible metal liner under the can end. By this method, the shelf life of the contents of the container is not diminished by metal exposure but, to the contrary, it is lengthened by many months.

The contents remain uncontaminated for a longer period of time than has heretofore been possible.

While the illustration and description have been directed to the placing of the frangible metal liner at one end of the illustrated can or container over the inner surface of the wall 14 and over the opening 15, with a vinyl coating over the inner surface of the metal liner, the liner may be seamed in both ends of the can, if desired, and the end wall 12 is illustrated as having such a liner disposed over the inner surface thereof and designated 25, whereby there is created added protection to the contents of the can against metal exposure and this frangible liner has a vinyl coating 25a thereover which is also secured in the end seam.

The seams here illustrated and designated 21a are of the form or construction illustrated in my copending application Serial No. 633,711, which seams more effectively provide the desired hermetic seal between the end and side walls by reason of the fact that the frangible metal liner covering the inner surface of each end wall is initially formed of sufiicient size so that when the seaming operation is carried out a substantial portion of the periphery of the frangible metal liner will be extended over the top of the can side wall and is squeezed and forced downwardly to a substantial degree between the outer side of the down-turned flange 26 of the can wall and the bent down peripheral portion 27 of the end wall or lid. As illustrated, this peripheral portion of the metal liner is rawn in this squeezing operation between the portions 26 and 27 to a tapered thickness as indicated at 28 and the edge terminates approximately half way down the height of the same over the down-turned portion 26 of the can flange.

Sealing or bonding material interposed between the flange of the can side wall and the down-turned portion 27 of the end wall is also compressed and squeezed down to secure the angle 29 which is formed by the bending back or bending up of the lip 34 of the can end wall so that this angle is completely secured with the sealing substance 31 and with the sealing substance so distributed in the angle together with the compression and extension or elongation of the peripheral portion of the frangible metal liner, there results a hermetic seal betwen the side Wall of the can and the applied end wall of greater strength and elfectiveness than has heretofore been attained.

In the described method for breaking and relieving stresses the formed opening in the end wall may be covered by a lining sheet or lamination of a lesser extent than that illustrated. For example, in our Patent 2,821,326, there is shown an end wall opening where in one form a liner covering the opening is secured around its periphery to the surface of the wall in place of having its periphery folded into the seam between the end and side walls. In another form the end wall opening is covered by a smaller patch lamination.

From the foregoing, it will be seen that by employment of the herein described method, a means is provided whereby beer and carbonated beverages may be canned without danger of the can or container rupturing because of high pressures therein. Also, by the disclosed method, canned commodities of the character referred to may be maintained free of contamination by the protection afforded in the event of abrasion of the container liner or tin plating and by reason of the improved hermetic sealmg.

In the use of cans of present known construction wherein there is or may be a vinyl coating or a vinyl or lacquer coating over the inner wall surface, when such cans are used for marketing or packaging commodities such as beer, carbonated beverages or other products under pressure, when the receptacle or can stands on end, there will be a head space of approximately $1 inch be tween the liquid and the can top. When corrosion starts in such a can, it starts at the bottom because the liquid is in contact with the bottom. This is brought about because the liquid is being forced by the pressure of the gases which may have accumulated in the head space against the coating of vinyl or the like, under such high pressure that the liquid begins to penetrate such coating and, the liquid being of an acid nature where beer, ale and carbonated beverages particularly are concerned, it attacks the tin plate coating over the steel base of the can and metal salts are formed which are dissolved in the liquid and spoil the same.

In the present invention where an aluminum foil is disposed over the inner surfaces of the ends of the can, and the foil is of course coated on its inner side with the vinyl coating as hereinbefore stated, the contents of the can is preserved for a much longer period of time, than is possible in conventional cans because if the vinyl coating over the aluminum foil develops or for any reason has formed in it a hole which will permit the liquid to pass through, the pressure will cause the liquid to enter between the vinyl coating and aluminum and when such acid liquid contacts the aluminum, aluminum salt, aluminum hydrate, is formed. In other words, an aluminum salt is produced which absorbs moisture forming the aluminum hydrate and as the liquid penetrates further, blisters are formed in the vinyl coating. These blisters do not break because the aluminum foil, being contacted by the acid carrying material and resulting in the formation of the powders which by the absorption of the liquid produces the aluminum hydrate, is protected by such substances. The salt thus formed prevents further action by the liquid on the aluminum and therefore the liquid is prevented from getting through to the metal undercoating and no metal salts are produced and no contamination of the liquid results.

In the event that the aluminum foil is used over one end only of the can with the. vinyl coating on its inner surface, then the contents of the can may be protected for a long period of time in the manner stated by seeing to it that the can is kept with the end having the aluminum foil coating thereover at the bottom so that the opposite end which does not carry the aluminum foil and vinyl protecting material will be separated from the liquid of the can by the gases in the head space.

We claim:'

, 1. A method of preserving beer, ale and carbonated beverages which react unfavorably with tin and steel in cans, having metal side and end walls, applying a protective permeable vinyl coating on the entire inner side and end Walls, at least one of said end walls being hermetically sealed to one end of the side wall and being of a metal of a higher negative rating than the metal of the side wall of the can, and the metal of the can side wall being automatically coated by an electrolytic action passing through contents of the can and through the permeable coating on the said one end wall of the can while the can is closed, and through the permeable coating on the metal of the side wall, and applying a sealed closure hermetically to the other end of the side Wall.

2. The method as defined in and by claim 1 wherein the said one end wall of the can presents an inner side of aluminum.

3. A can for beer, ale and carbonated beverages and having metal side and end walls, a protective permeable vinyl coating on the inner surface of the side wall and end walls, and means for preventing spoilage in the can of material of a nature to react unfavorably. with the metal of the can where the metal is exposed through the protective coating, which means comprises at least one of the end Walls of the can having the permeable vinyl coating on its entire inner surface, said one end wall having a higher negative rating than the metal of the side wall so that through electrolytic action. any exposed metal of the side wall is coated by the said metal of the said one end wall.

4. The can as defined in and by claim 3 wherein the said inner surface of said end walls is aluminum.

References Cited in the file of this patent UNITED STATES PATENTS 2,479,409 Roedil Aug. 16, 1949' 2,790,577 Fried Apr. 30, 1957 2,821,326 Fried Jan. 28, 1958 

1. A METHOD OF PRESERVING BEER, ALE AND CARBONATED BEVERAGES WHICH REACT UNFAVORABLY WITH TIN AND STEEL IN CANS, HAVING METAL SIDE AND END WALLS, APPLYING A PROTECTIVE PERMEABLE VINYL COATING ON THE ENTIRE INNER SIDE AND END WALLS, AT LEAST ONE OF SAID END WALLS BEING HERMETICALLY SEALED TO ONE END OF THE SIDE WALL AND BEING OF A METAL OF A HIGHER NEGATIVE RATING THAN THE METAL OF THE SIDE WALL OF THE CAN, AND THE METAL OF THE CAN SIDE WALL BEING AUTOMATICALLY COATED BY AN ELECTROLYTIC ACTION PASSING THROUGH CONTENTS OF THE CAN AND THROUGH THE PERMEABLE COATING ON THE SAID ONE END WALL OF THE CAN WHILE THE CAN IS CLOSED, AND THROUGH THE PERMEABLE COATING ON THE METAL 